RECOMENDACIONES TÉCNICAS Y DE METODOLOGÍA

Contractor's cost items: management and staff (A40)

The estimator in pricing this item will make use ofa form similar to that in Table 4.1.

Table 4.1 On-site supervision

General foreman 1 450 200 650

Section foreman

Trades foreman 1 400 200 600

Engineer 0.1 0.1 750 150 90

Engineer's asst 0.1 0.1 550 150 70

Chainman 0.1 350 125 48

Quantity surveyor 0.2 0.2 800 200 200

QS asst Office manager Wages clerk Timekeeper

Cost clerk 1 450 200 650

Typist

Safety officer 0.1 0.1 550 150 70

Plant manager Foreman fitter

Total per week 4.6 1.5 3128

Cost ofcars 1:5  £150 225

Petty cash/expenses 4:6  £75 345

Stationery 4:6  £40 184

First aid/laundry 4:6  £425 115

3997  52

Total cost ofsupervision £207844

* Staff/car numbers: 1 day/week ˆ 0:2, 1 week/year ˆ 0:02.

Contractor's cost items: site accommodation (A41)

This item comprises the accommodation required by the contractor in addition to that described in the bills ofquantities for the use ofthe architect or contract administrator and/or the clerk ofworks. The cost ofsite accommodation includes (offices, laboratories, cabins, stores, compounds, canteens, sanitary facilities and the like) the two components of weekly hire plus the cost ofset-up and takedown. For the factory example the cost is as follows:

Weekly hire

Staff offices: 1 unit 15 m  3:6 m at £100/week £100 Clerk of works office: 1 unit 5 m  3:6 m at £60/week £60 Operatives' mess room: 1 unit 15 m  3:6 m at £100/week £100 Materials store: 1 hut 9 m  6 m at £55/week £55 Portaloo 3 cubicles, 3 urinals: 1 nr at £60/week £60

Total weekly hire (includes furniture) £375

Total costs

Accommodation for 52weeks at £375 £19 500

Transportation to and from site, and set-up and take-down £750

Connection of services: 20 hours at £8.00 £60

Total cost £20 410

Contractor's cost items: services and facilities (A42)

The services and facilities item is to cover the cost of power, lighting, fuels, water, telephone, safety, health and welfare, storage, disposal, cleaning, drying out, protection of work, security, maintain roads etc. These are listed and costed as follows:

Electricity

Connection charge £250

Wiring (included in office unit):

Electrician 5 hours at £8.00 £40

Materials £75

Cost of electricity 52at £15 £780 £1145 Water

Temporary connection £100

Water charges at £0.02per m³ £400 £500 Telephone

Connection (site line) £150

Connection (clerk of works line) £150

Fax/answering machine £400

Call/rental charges (site) at £250/qtr 1000

Ditto clerk of works (provisional sum) £500 £2200

Local authority rates

On-site accommodation £1500

Fire precautions

Extinguisher maintenance £150

Rubbish disposal

One skip per week at £60 £3120

Cleaning

Offices etc. 52  5 days

2hours/day at £6.50 £3380

Site 52  5 days, 2hours/day at £6.50 £3380

Roads (as necessary) say £1000

Professional cleaning on completion £1500 £9260

Drying out

Dependent upon the time of year, the work of wet trades may need to be dried either by heating or by dehumidification. The example project will not need this.

Small plant and tools

This covers small plant, which the contractor owns as opposed to hired plant. It includes such items as small mixers, 110 volt transformers, power hand tools, picks, shovels, etc.

The cost is based upon a percentage of the project cost, say 0.20 per cent of £1 000 000. £2000 General attendance on nominated subcontractors

The bills of quantities measured in accordance with SMM7 will contain this general item for all nominated subcontractors. It allows the contractor to reflect the cost of providing messing and other facilities for the operatives of nominated subcontractors. In the pricing of the example contract this cost has been included in item A41 by an extra allowance in the sizing of facilities.

Site transportation

It is normal to make an allowance for a site van. This will be an all-purpose 1 tonne van for sundry collections and other errands. It will be driven by an employee and may be in the overall care of the general foreman.

1 nr 1 tonne van at £115/week £5798

Contractor's cost items: mechanical plant (A43)

This item allows the contractor to price for large items of plant (including cranes, hoists, personnel transport, earth moving plant, concrete plant, piling plant, paving and surface plant, etc.) the cost ofwhich may not be totally related to one work section. A tower crane, for example, would be used for lifting skips of wet concrete for in situ work, steel sections, precast units, etc. The cost of the tower crane would be difficult to distribute amongst these items and therefore its cost is better reflected here.

Also, in situations where work is marked as provisional, the contractor may wish to price the plant associated with that work under this section. For example, the bills ofquantities may indicate piling comprising 100 driven precast concrete shell piles provisionally 15 m long. Ifthe project demanded two piling rigs for three weeks at a cost of£3500 per week

each, then the cost may be included as a lump sum of£21 000 in this section or alternatively as £14 per metre ofpiling.

The problem with the latter alternative is that the period that the rigs are required on site is related as much to the number ofpiles to be driven as to their total length. Ifeach pile were driven 14 m instead of the 15 m anticipated, this would be unlikely to have any effect upon the total time that the rigs were required on site. However, had the pricing been based upon

£14 per metre ofpiling the contractor would have received £1400 less income.

Contractor's cost items: temporary works (A44)

This item is provided in the bills ofquantities for the pricing ofany temporary works which is not to be included as an element ofthe bill rate. Temporary works which may be included are temporary roads, temporary walkways, access scaffolding, support scaffolding and propping, hoardings, fans, fencing, hard standing and traffic regulations. In the example factory, scaffolding is to be considered as an item under this heading. Scaffolding is most commonly provided by a specialist scaffolding company, which will quote for the erection and dismantling of scaffolding plus a hire rate per week.

It is assumed for the purposes of the example that scaffolding will be provided by the contractor for the brick office structure to be constructed within the framed building. From the information given in the description of the works it is assumed that a freestanding scaffold will be required 48 m long  4:5 m high  1:2 m wide.

The names given to the various scaffolding components are as follows:

Standards Vertical tubes 1.2 m apart, at 2 m centres along the face and back of the scaffold.

Ledgers Horizontal tubes running the length ofeach side ofthe scaffold, at 1.5 m vertical centres.

Putlogs Horizontal tubes across the width of the scaffold, at 2 m centres horizontally and 1.5 m centres vertically.

Braces Diagonal tubes across the face and back of the scaffold.

Boards Decking and toe boards.

The costs are calculated as follows:

Quantities

Standards: [(48/2) ‡ 1]  2 ˆ 50  4:5 m high 225 m

Ledgers: (4:5/1:5)  2  48 m long 288 m

Putlogs: [(48/2) ‡ 1]  4:5/1:5)  1:5 m long 113 m

Braces: say 72m

Total tube 698 m

Fittings: say 4 per putlog (300) ‡ 60 ˆ 360

Boards (225 mm wide): 5 boards ‡ toe board ˆ 6  48 m ˆ 288 m Erect and dismantle time

Tube: 698 m at 0.1 hours/metre 70 hours

Fittings: 360 at 0.15 hours each 54 hours

Boards: 288 m at 0.06 hours/metre 17 hours

141 hours

Cost: erection and dismantle plus hire six weeks

Labour: 141 hours at £8.00 per hour £1128.10

Hire: Tube 698 m at £0:05/m per week  6 weeks £209.40 Fittings 360 at £0:02each per week  6 weeks £43.20

Boards 288 m at £0:08/m per week  6 weeks £138.24

Transport: say 5.5 tonnes at £30 inc. loading and unloading £275.00

Cost of scaffolding £1793.84

Work/products by/on behalf of the employer (A50)